1. Field of the Invention
This invention relates to a variable refrigerant package (VRP), and more particularly, to a variable refrigerant package that may be quickly installed in new construction.
2. Description of the Prior Art
A package terminal air conditioner (PTAC) and a vertical packaged air conditioner (VPAC) are types of self-contained heating and air conditioning systems commonly found in hotels or motels. Most PTAC and VPAC units are designed to go through a wall having vents and/or heat sinks both inside and outside. While PTACs and VPACs are commonly used to heat or cool a single living space, there are cooling only PTACs and/or VPACs with an external heating source. On some PTACs/VPACs condensate drain piping is not required because the condensate water extracted from the air by the evaporator coil is thrown by the condenser fan onto the condenser coil surface where it evaporates. Conventional PTACs/VPACs still require condensate drain piping to be installed.
Through-the-wall units such as PTACs/VPACs have some basic problems. The through-the-wall units do not ventilate the space in which the air is being conditioned. If provisions are made to ventilate the space being conditioned, then humidity is introduced into the space being conditioned. For example, in coastal areas, motels/hotels have a tendency to have a musty smell due to the humidity. The problem is the unit does not run long enough to remove the moisture from the space being conditioned. Yet, building codes require ventilation of the areas being conditioned which PTAC/VPAC units do not normally provide.
While there have been various attempts to reduce the humidity inside of the space being conditioned, such attempts normally require ancillary devices or systems other than the PTAC/VPAC unit. Some require separate dehumidifiers that have to be connected to a building drain. Others require separate dehumidified air being forced into the conditioned space. Each of these systems are either complicated, expensive, or do not work properly.
The standard air conditioner as it is cooling a particular space only responds to the temperature inside the space. Once the space's temperature is satisfied, the active cooling and dehumidification of the space stops. Humidity in the space continues to build. One solution to address the dehumidification and ventilation that has been used in the hotel/motel industry was to have duct work connecting a source of dehumidified outside air to the enclosed spaced. The dehumidified outside air is forced through the duct work into the room. The increased pressure caused by forcing the dehumidified outside air into the room being conditioned escapes through leakage points such as around the entry door and through the room exhaust. However, this method requires the running of additional duct work and having a dehumidifier to remove moisture from the outside air.
Another common method that was used was to have a flap inside of a PTAC unit that is opened to allow outside air to be brought in. However, the outside air was not dehumidified which adds humidity to the space and would many times cause a musty smell inside of the room. Many times after inspection the outside air flap was simply bolted shut.
Another variation of the room air conditioner is what is called a variable refrigerant flow system (VRF). Those systems have very large outdoor condensers and multiple indoor evaporators with refrigerant tubing being run to every space being cooled. Still, the variable refrigerant flow systems continue to have problems with high humidity and lack of available ventilation air.